Process of making lubricants



Patented May 22,1945

PROCESS OF MAKING LUBRICANTS Mathias Pier, Heidelberg, and meal-res Chl'iitmann, Ludwigshafen on the Rhine, Germany; vested in the Alien Property Custodian No Drawing. Application December 2, 1937, Se--- rial No. 177,745, which is a division of application Serial No. 651,802, January 14, 1933. Divided and this application March 27, 1940,

Serial No. 326,156. 1932 Claims.

The present invention is concerned with the production of lubricants, more particularly with the production of substances which are either good lubricants themselves or which are valuable improving agents for other lubricants.

We have found that particularly valuable lubricating oils are obtained by subjecting the said parafiin waxes or similar waxes rich in hydro-gen or mixtures containing the same, for example mixtures with hydrocarbon pilsrich in hydrogen (petrolatum) or with fats, fatty oils, other waxes, high molecular alcohols or esters or acids, such as stearic acid, palmitic acidor oleic acid, tocondensation by means of the action of silent electric discharges. The condensation products thus obtained may also be employed with advantage asadditions to lubricating oils. They have the efifect of improving the properties of the latter;

in particular the pour point of the lubricating oils is lowered to an appreciable degree. By the term parafiln wax we means paraflln wax from any origin, as for example from mineral oils or from brown coal, as well as waxes consisting of solid isoparafllns (by which we' mean parafilnic hydrocarbons having branched carbon chains), as for example Palembang wax, or dehydrogenated paraflln waxes, which may be dehydrogenated by heat-treatment, such as, preferably slight, cracking or by introducing into the initial parafiin wax an exchangeable substituent, such as a halogen or sulphur or oxygen, and subsequently splitting off the hydride of the said substituent at an elevated temperature, preferably in the presence of a cata- The acid treatment of paraifin waxes or similar waxes with silent electric discharges is hereinafter referred to as "voltolization.

We have further found that by suitable modifications or special modes of proceeding the results arrived at by the said voltolization' may be i considerably improved. Careful investigation of the phenomena occur- In Germany February 8,

results as when employing materials.

the said peculiar initial We further found that the products obtained by rendering harmless of the'said obnoxious constituents contained in the voltolization products. We further discovered that by carrying through the vo'ltolization treatment under quite specific conditions products may be obtained possessing one or the other quite peculiar characteristic which therefore are particularly valuable under certain circumstances.

The properties of the .voltolization products obtained according to the present invention vary to a more or less substantial extent with the nature of the initial materials subjected to voltolization, with the conditions employed for the voltolization treatment and also with the nature of the further treatment of the crude products resulting from the treatment with silent electric discharges. In view of these varying properties the productsobtained according to our present invention may be used as lubricants, L e., lubricating oils or greases, or when being less mitable for direct use as lubricants, they are highly valuable agents for improving other lubricants, imparting to the latter particularly valuable properties. Our present invention is also concerned with such compositions containing voltolization products as improving nts.

More specifically, it is an object of the invention to provide a process for after-treating and improving the products of voltolization obtained by the procedures'described in detail in our copending applications Serial No. 651,802, filed January 14, 1933, now U. 8. Patent 2,197,768, issued April 23, 1940, and Serial No. 177,745, filed De- .cember 2, 1937, now U. S. Patent 2,197,769, issued April 23, 1940.

The method of treating initial materlalsof the kind described above will however be explained further by wayof two specific Examples.

Example 1 Ceresine having a melting point 0! 73 C. is treated at temperatures above its melting point,

as for example at from to -C., in a Siemens ozonization tube under a, pressure of from about 5 to 10 millimeters (mercury gauge) with electric discharges at about 7000 volts and 1000 cycles hardparamn wax having a melting point of 50 C. l The immunization" or removal of the obnoxbeing added as a diluent after from 20 to22 hours. ious substances present in the crude voltolization The resulting mixture is then subjected to a products may be effected by means of an extracvacuum steam distillation up to 280 C. whereby tion process in which hydrocarbons gaseous at sthe added paraflin wax and any products of low 6 ordinary temperature which have been liquefied boiling point formed are distilled ofi. by cooling and/or the application of elevated Example 2 pressure are preferably used as extractionagents. I For this purpose the voltolization product is A P r wax Obtained from a mineral oil n mixed with from 4 to 6 times the amount of lique- Whioh has a mean molecular Weight of 340 i 10 fied gaseous hydrocarbons as for example methtreated in the fused state at between about 80 ane ethane, propane, b t n ethylene, propylene in a S eme s o o e-t tube or mixtures thereof. It is preferable to employ about hours with electric discharges at about propane or ethane r mixtures of propane and 17000 volts and 10000 Hertz while maintaining a ethane. The said treatment is effected in a vesivacllum of about 10 mete m y gaugesel capable of withstanding elevated pressures 1 A slalve like Product is t s o t e from which whereby a pressure prevails which is equal to the by subsequent distillation in vacuo at about 270 vapor pressure of the particular liquefied hy- C. an oil hav n a Viscosity of E at drocarbons or of the particular mixture of liqueis obtainedfied hydrocarbons at the working temperature,

As has been pointed out above We have found 20 which is either ordinary or slightly reduced temthat the products resulting from the voltolization perature. In this manner the lower molecular treatment can be. improved by subjecting them to constituents present in the voltolization product i after-treatment more p t ula ly w a v are dissolved by the solvent while the valuable 1 to immunize obnoxious constituents which are portion of this product remains undissolved. The y P se in se p d They often two layers formed are then separated. By lower ;contain more or less substantial amounts of parafing th temperature stepwise, products having hydrocarbons of the order of those present difierent characteristics may be precipitated from 111 ordinary ft o d paraffin W of a the solution in the liquefied hydrocarbons.

b gher order. We have therefore attempt It is also possible to dilute the crude voltolizato improve the crude products by removing theretion products with lower molecular hydrocarbons from Such, Darafiin W hydrocarbons, for such as gasoline or kerosene or the like, then to ample by freezing them out. It has been foun cool the mixture and to remove the substances, however, that While such treatment often leads in, particular the parafiin waxes which have been to a very substantial improvement'of the crude separated t,

voltolization products it does not render them In this case the voltolization product is preferfree from objectionable matter in all cases. ably diluted with benzine or illuminating oil or F111 the! v t ation has revealed the fact that with halogenated hydrocarbons such as trichlororing the voltolization treatment comparatively ethane, then cooled to a temperature between large quantities of products of middle oil eh 1- 8 and 30 below zero C. whereby the paraflin acter are formed and that it is due to such conwax contained in the crude product is precipistituents of middle oil character that the voltated, the latter then being filtered or centri tolization products hitherto known and often also fuged- The solution containing the valuable con- 1 those ta ned as hereinbefore desc b d d not stituents of the voltolization product and the low meet requirements of practice- We have boiling constituents thereof is then freed by dis- 1 therefore found it necessary to immunize no tillation from the diluent and from the said low y P n W hydrocarbons but also middle boiling constituents. This product may also be oils either by removing both kinds of Sub first freed from the low boiling constituents and 1 or y removing O y e Constituents of middle from the bulk of the parafiin wax and then sub- 011 character and otherwise rendering harm jected to the aforesaid cooling operation. The ;the paraflin wax hydrocabons. paraifin wax' separated from the voltolization y the presence of these substances in the volproduct may again be supplied to the voltolizai tmile-tion P s t e high q y of the latter tion treatment. If the cooling operation is car- (the tests of which are much better than those i t stepwise the paramn wax may be got the natural or synthetic lubricants hitherto tained in t form of ingle fractions Yknown) is ppr ably a t d- The v i This method of operation will be further detion product are impaired by the said substances scribed by the following example.

in particular as regards their flash point, their setting point, their viscosity and their capacity m 3 I of forming films. If, however, the voltolization A voltolization product as obtained in the manfproduc'ts are subjected to the aforesaid imnor described in Example 2 is diluted at ordinary gmunization, products having excellent properties temperature with the double amount of benzine. j are obtained; for example the films formed there- The solution is then cooled to 0.? C. whereby parfrom are only difiicultly broken even if two parts afiin wax is precipitated in an amount of 40 per 10f a machine are pressing with a. high pressure cent of the said voltolization product. This par- ?against each other. The said after-treatment is aflin wax is separated from the solution by filterlalsoiof particular advantage in case the voltolizaing or centrifuging. The remaining solution is tion products are to be employed for improving then distilled whereby benzine and middle oil lother lubricating oils since the efiect attained-by are evaporated. The residue represents an oil fa certain amount of such product is considerably ,havinga viscosity of 16 Engler at 99 C. .:greater than the efl'ect obtained by the same Z0 We have also folmd that the crude voltolizaiammmt of a voltolized product which has not n'on products may be dissolved in solvents as for subjected to the said after-treatment, in example ether or kerosene; whereupon such subas regards the lowering of the pour stances as acetoneare added whereby the valjpoint, the improvement of the-viscosity index and liable constituents of the crude product are prethe capacity of formingfllrll. i cipitated out.

asvasor Y 3 This operation may be carried out as follows:

The crude voltolization product is dissolved in a solvent, as for example ether, whereupon the pure voltolization product is precipitated by means of a precipitant, such as acetone. This treatment may also be eilected in stages, whereby-pure voltolization fractions having different viscosity may then be employed for improving lubricating oils while the fraction having the iower viscosity may be used as such as a lubricant. The said precipitation may also take place at a subatmospheric temperature, in which case the temperature may be lowered in stages. In this manner the paraflin wax present in the crude voltolization products is precipitated, after the precipitation of the valuable constituents of the said products, if desired in the form of two or more fractions having a different mean molecular weight, while the low boiling constituents formed during the voltolization remain dissolved in the solvent. The voltolization product may also be dissolved in other solvents and precipitated by other precipitants; Thus it may bedissolved in ether and precipitated by alcohol or dissolved in trichloroethane and precipitated by acetone.

The following example further illustrates this feature of our invention.

' Example 4 A voltolization product as obtained according to Example 2 is dissolved in twice the amount of ether whereupon acetone is added in an amount half that of the ether in three equal portions. In this manner at first per cent of the voltolization product are obtained as a substance having a viscosity of Engler at 99 C., after the second addition 25 further per cent of .a product having a viscosity of 20 Engler at 99 C. and after the third addition 25 per cent of a product having a viscosity of 8 Engler at 99 0. bein precipitated. Th portions precipitated in the single stages are removed from the body of solvent by decantation and then separated from adhering parts of the solvent, for examp e by distillation. The solution is then cooled to 10 below zero C. whereby paraflin wax is precipitated in an amount of 10 per cent ofthe initial voltolization-products. The remaining solution is then separated by distillation into ether, acetone, middle oil and, in an amount of about 15 per cent of the voltolization product, a low boiling lubricating oil having a viscosity of 4 Engler may also be dissolved and then precipitated, if

desired in stages, by means of a precipitant. Still another method consists in first hydrogenating the crude product and then subjecting it to" voltolization and working up the crude reaction products, the products may vary widely in their properties. l v

Generally speaking it may be said that the voltolization products are mostly characterized by the following properties:

Theyhave a viscosity index of between about 120 and 150, more particularly between 130 and 150, in preferred cases between 140 and 150. The viscosity at 99 C. ranges between -3 and 150 Engler or is even higher, as a rule between 9 and 80 Englerand more, usually between 12 and 60 Engler; the molecular weight determined in benzene ranges between 500 and 10000, as a rule between 600 and 5000 and more,.usually between 800 and 2500; the specific gravity is about 0.86. The products contain between about 16 and 16.3 parts of hydrogen for each 100 parts of carbon, they have a Conradson carbon test of between 0.6 and 0.05, more usually between 0.4.and 0.1, a flash point between 280 and 330 C., and in any case above 300 C. if the viscosity at 99 C. is higher than 5, and a tar value below 0.4. Their color is from light yellow to dark yellow. I

Thus for example a voltolization product which may be directly employed as a cylinder oil has a molecular weight between 800 and 1000, a viscosity between 5 and 10 Engler at 99 C., a viscosity index between 130 and 150, a carbon test between 0.4 and 0.6 and contains 16.4 parts of hy- V drogen for each 100 parts of carbon.

a cooling operation, or flrstto dissolve the crude product. then precipitating it by means of a pre cipitant and finally purifying the precipitate thus obtained by dissolving it in a solvent and then precipitating it by cooling the resulting solution.

The products obtained according to the proces of the present invention are either valuable I The voltolization products which may be added to lubricating oils for improving their properties as a rule have a molecular weight above 900., for example between 900 and 2000 or even higher and a viscosity, at 99 C., between 12 and Engler. as for example 40 or 60 Engler. But also less viscous products having for example a viscosity between 4' and 10 Engler at 99 C. may be employed for the said purpose. The amount of the voltolization products added to the lubricating oils depends on the properties of these products and on the viscosity index to be imparted to the lubricating oil to be improved.

Crude voltolization products which are only freed from the low boiling constituents formed during the voltolization have the consistency of fats. when lubricating greases are to be prepared directly by the voltolization the treatment is continued until a viscosity at 99 C. of between 30 and 80 Engler or higher, such'as of 50 Engler is attained The resulting products have a solidification point of between 30 and 35 C. and a dropping point of about 30 C. These products may also be employed in admixture with other lubricating greases.

Generally speakin the voltolization products substantially improve the pour point of lubricants when added thereto in small amounts, and the temperature viscosity curve. i. e., the viscosity index when added in comparatively large amounts.

In addition to having the aforesaid properties. the'products obtained from the said mixtures, especially from pa'rai'fin waxes of high molecular weight or their derivatives and hard or soft paraiiln. wax or oils rich in hydrogen containing the same, by voltolization treatment are 'excellent solid lubricants by themselves and it is not voltolization products. Turning now to the improvement of the, viscosity index of lubricants by the addition of voltolization products, we have found that polymerization products prepared in the said manner and having a viscosity of more than preferably more than 12 Engler at 99 C. are particularly valuable in that by the addition even of small amounts thereof to lubricating oils having an unsatisfactory temperature-viscosity curve, a considerable improvement in the same is effected. The advantage of this modification of our present invention resides in the fact that the improvement in the temperature-viscosity curves of any lubricating oils, especially of those having steep temperature-viscosity curves, is very considerable even by the addition of small amounts of the highly viscous condensation products. With large amounts of addition, there is only-a slight further increase in the improvement.

' These highly viscous products may also be prepared from a voltolization product of low viscosity by dissolving the latter in a solvent and then precipitating from the solution the higher viscous portion.

ture-viscosity curve of lubricating oils when added thereto in amounts of from 0.5 to

10 per cent or more.

When separating paraffin wax or other waxes' from hydrocarbon products containing the same,

such as mineral oils, tars, products obtained by the extraction of coals or tars or by the destructive hydrogenation of carbonaceous materials of the nature of coals, tars and mineral oils, difficulties are often encountered in the mechanical separation of the precipitated constituents since the precipitate constitutes a smeary mass from which the solid portions can be separated only with difficulty. By the addition of small amounts of the voltolization products obtained as hereinbefore described the said solid portions may be easily separated from the body of oil.

An addition of voltolization products proves valuable not only when added to lubricants having a high pour point due to the presence of parafiin wax, but also in the case of hydrocarbon mixtures which contain crystallizable cyclic hydrocarbons which are soluble in oil.

Also in this case, the oil obtains a good mobility even at low temperatures. As initial oils may be mentioned for example tar oils or fractions thereof, especially coal tar oils containing naphthalene, anthracene and carbazole which crystallize out at low temperatures thereby rendering their employment troublesome. We have found that this crystallization is prevented by the said additions.- I

The following example .will further illustrate this feature of the present invention.

Example 5 A tar fatty oil containing small amounts of .anthracene and carbazole which has been obtained from coal tar oil by distillation has a setting point of 12 below zero 0. 'By adding 1 per cent of a condensation product of paramn wax prepared according to Example 2 the set- .ting point is lowered to 20 below zero C.

We have also found that the highly viscous,

oily product described above considerably iniproves the color of lubricating oils when it is added thereto. Furthermore the other properties of the lubricating oils, as for example the setting point and viscosity, may also be improved by the addition, An addition of a few tenths of one per cent is sufficient to impart to a non-fluorescent lubricating oil a strong fluorescence such as is frequently required in commerce. Of course also greater amounts of .the said resinous products may be added if so desired.

An addition of vololization products proves valuable also in the case of lubricating greases (also known as consistent greases) as for example those used for driving gear, differential gear and similar apparatus, which in some cases become hard and stiff at comparativelylow tembility of such lubricating greases, at low-tem-' 4 peratures is considerably improved by adding thereto synthetic products of the aforesaid kind, obtained by the treatment of hard or soft paraffin wax or derivatives thereof or montan wax, or substances containing the said products in considerable amounts, such as petrolatum, crude parafiin wax, petroleum jelly or crude lubricating oils containing parafiin wax or high molecular alcohols or esters, if. desired in admixture with paraflin wax, with high voltage. preferably high frequency, electric currents.

Generally speaking it is preferable to add from 0.5 to 5 per cent of the synthetic products to the lubricating grease to be improved, but larger amounts,'as for example 10 or 20 percent or more maybe employed. In the case of lubrieating greases which are not to be used under extreme conditions anaddition of less than 2 per cent, as for example 1 per cent is sufiicient 'low temperatures a better mobility, a smaller resistance to friction, a greaterlubricating action, may be more readily pumped and cause a better engagement of the gears than the original grease. When employing the greases as gear greases, the gears are less worn and the temperature of the gear housing is not unnecessarily increased. 7

The voltolization products may also be very useful when added to lubricants in conjunction with other addition agents.

Thus we have found that oils containing hard or soft paraflin wax, especially lubricating oils, gear oils. lubricating greases and gear greases, are much improved by adding thereto small amounts of high molecular hydrocarbons which.

even in small amounts, increase the viscosity and also such voltolization products as are capable "of lowering the setting point. Ithas been found that the additions exerting eifects in the differensured. voltolization products to motor fuels the valves As oils containing parafiln wax may be mentioned especially those which have a high flash point, as for example Mid-Continent oils, Pennsylvanian oils, lubricating oils, still containing hard or soft parailin obtained by destructive hydrogenation, or oils containing paraffin wax which have been treated with liquefied hydrocarbons which are gaseous at room temperature,

with phenols, with sulphur dioxide or with other solvents or extraction agents.

In order to increase the viscosity and improve the temperature-viscosity curve, hydrocarbons having a molecular weight of more than 1000, preferably of more than 2000, are added to the said oils; these added hydrocarbons should have" the property of exerting a favorable effect in this direction even when added in small amounts.

According to this feature of our invention there is also added to the improved oils a small amount, as for example from 0.5 to per cent,

of a voltolization product which lowers the setting point, most suitably such as is obtainable by the voltolization of hard or soft paraflin wax (as for example petrolatum) or of paraflins havinga molecular weight .of more than 330 or of Inadditi'on, our voltolization products also offer great advantages when adding the said substances to hydrocarbon mixtures other than lubricating oils, as for example to benzines, gas oil, illuminating oil and parafiin wax.

The advantages of the process in the case of liquid hydrocarbons consist in the facts that their viscosity is increased and a better capacity for being pumped and a smaller consumption are Furthermore when adding the said in the combustion space of the motor are continually lubricated and the piston rings are more tightly connected with the cylinders. In the case of paraflin wax the viscosity of its melt is increased and after cooling no cracks appear or, in cases when they do appear,- they rapidly disappear again.

voltolization products may also be used for special purposes, as for example when for the operation of aeroplane engines, highly sensitive automobile engines and the like, lubricating oils having a viscosity index of more than 120, a flash point of more than 230 C., a Conradson coke test of less than-1, a viscosity .of from 2 to Engler at 99 C. and in some cases a setting point of lower than 10 below zero C., are required. The preparation of such lubricating oils is, however, very troublesome and expensive by the usual methods.

We have found that lubricating oils having the said properties are obtained in a comparatively simple manner by adding to lubricating oils obtained by the destructive hydrogenation of paraffln basic mineral oils or fractions thereof of high boiling point, the condensation products obtainable by the voltolizatio'n of hard or soft parafiin waxes.

As the first-mentioned component may be mentioned especially destructive hydrogenation products of Pennsylvanian, and also, lideslred, of Mid- Continent, oils especially their lubricating oil fractions. For example lubricating oil fractions having a viscosity index of from 80 to 110, especially from 100 to 110, a viscosity of from 2 to 8 Engler, at 99 C., especially of from 25 to 6 Engler at 99 C., a coke test of more than 0.5, especially of more than 1, and a. flash point of from 200 to 320 C., especially of from 230 to 290, C., may be subjected to destructive hydrogenation. In this way a lubricating oil is obtained having a viscosity of from 2 to 3 Engler at 99 0., a-viscosity index of from 100 to 120, advantageously from 110 to 120, a'coke test of from 0.05 to 0.5 and a flash point offrom 200 and a coke test of from 0.3 to 0.2, especially 'of from 0.3 to 0.1.

These products may also be employed in admixture with hydrogenation productsof rubberor of polymerization products of diolefines, such as butadiene, or of cyclo rubber or resins free from oxygen or of polymerization products of olefines, such as isobutylene. I

The voltolization products together with the parafiin wax contained in the crude product or after separation thereof may be employed in admixture with-a white 011 of any desired viscosity, for example with parafiinum liquidum for pharmaceutical or cosmetic purposes. In this case the said products may also be stirred with small amounts of water or preferably purified before use. I

The voltolization products may also be employed together with water as lubricants.

It should be noted that whenever in the forego. ing examples we have spoken simply of parts, what we mean thereby is parts by weight.

This application is a division of our copending application Ser. No. 177,745, filed December 2, 1937 now U. S. Patent No. 2,197,769, issued April 23, 1940, which in turn is a division of our copending application Ser. No. 651,802, filed January 14, 1933, now U. S. Patent No. 2,197,768, issued April 23, 1940, wherein the various ways of applying our improved voltolization products are described in greater detail with the aid of specific examples. 1

While in the foregoing we have explained our invention by reference to specific examples, we wish it to be understood that our invention is not in any way limited to these specific examples,

the scope of our invention being def ned in the "the solution formed to a temperature between about -8 and 30 0., thereby precipitating paraflln wax, separating said wax from the solution and recovering the desired products from the wax-tree solution.

2. The process for producing lubricants and products suitable for improving lubricants from tion formed a precipitant for the condensation products in stages of such succession as to successively precipitate condensation products of different viscosities, separating the precipitate from the solution and recovering the desired products from the separated precipitate.

3. A process as claimed in claim 2 which comprises, cooling the solution remaining after the precipitation of the condensation products to a sub-atmospheric temperature so as to precipitate paraffin wax.

4. The process for producing lubricant and products suitable for improving lubricants from aliphatic waxy material which comprises subiecting said material to the action of silent electric discharge for a time suflicient to form condensation products having a viscosity of at least 3 Engler at 99 C. and being soluble in hydro carbon lubricating oils, mixing this thus treated material with a selective solvent, adding to the solution amaterial for precipitating from the mixture portions of relatively low solubility in the solvent used while maintaining portions of high solubility dissolved, separating said portions of relatively low solubility, cooling the resultant solution to precipitate paraiiin wax therefrom, and recovering the desired product from the wax-free solution.

5. The process for producing lubricants and products suitable fOr improving lubricants from aliphatic waxy material which comprises, subjecting said material to the action of a silent electric discharge for a time suflicient to form condense-tion products having a viscosity of at least 3 Engler at 99 C. and being soluble in hydrocarbon lubricating oils, diluting the thus treated material with a selective solvent, cooling the solution formed to a temperature between about --8 and -30" 0., thereby precipitating paraflin wax, separating said wax from thesolution and recovering the desired products from the wax-free solution.

MATI-IIAS PIER. FRIEDRICH CHRISTMANN. 

